Brussels: The European Union (EU) on Sunday condemned the terrorist attack at a Coptic church in Cairo which claimed 25 lives and wounded 49 others.

"Today's terrorist bombing at Cairo's Coptic cathedral during Sunday mass has exacted a terrible toll of civilian deaths and injuries," Xinhua news agency quoted spokesperson of the European External Action Service (EEAS) as saying.

"Our thoughts now are with the victims and their families. The EU expresses its condolences to the bereaved and stands side by side with Egypt in the efforts to defeat terrorism in their country," the spokesperson added.

Earlier in the day, a bomb went off inside the al-Botrossiya Coptic Church in Cairo's Abassiya neighbourhood that was full of worshippers attending Sunday mass, leaving 25 people dead and 49 injured, ten of them in critical condition, according to the Health Ministry.

Security sources told state-run MENA news agency that initial inspections revealed the blast was caused by a 12 kilogram highly-explosive TNT bomb. No group has claimed responsibility for the attack so far.

However, fingers are pointed at the Islamic State-affiliated Ansar Bayt al-Maqdis (ABM) group which operates in the country's restive North Sinai province.